Various improvements have been proposed to enhance the performance of light emitting devices using semiconductor light emitting diodes (LED). For example, U.S. Pat. No. 6,307,218, entitled “Electrode structures for light emitting devices” and assigned to Lumileds Lighting, U.S., LLC, discloses finger type electrode layouts to solve the current crowding issue in semiconductor LEDs. U.S. Pat. No. 5,998,925, entitled “Light emitting device having a nitride compound semiconductor and a phosphor containing a garnet fluorescent material” and filed by Shimizu et al on Jul. 29, 1997, discloses generation of white light through phosphor conversion of a portion of the primary radiation emission of the an LED device to longer wavelengths.
Nevertheless, further improvements may still be desirable. For example, few conventional designs have considered the heat dissipation and energy consumption issues. These issues may become more noticeable if the LEDs have a relatively large size.
In addition, in order to achieve good current spreading in the semiconductor layers and to avoid over-heating in partial areas caused by possible relatively high current in such areas, the design of the '218 patent may need to have a relatively compact electrode layout design. As a result, the opening area for light emission may be unnecessarily small, which may not be desirable, either.